K-Celebs who use songs by other people as ringtones:
Eli – U-Kiss [all be there by usher]
Minji – 2NE1 [Love the Way You Lie - Eminem and Rihanna]
Ga-In – BEG [Christmas Song by Faith Evans]
Narsha – BEG [Like a Star by Corrine Bailey Rae]
Rana – 9Muses [Beautiful Thing by Xiah Junsu]